考察理解题目的能力, 上代码:

import java.io.BufferedReader;import java.io.InputStreamReader;public class Main {    public static void main(String[] args) throws Exception{        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));        int num = Integer.parseInt(br.readLine());        int oneNum = 0;        int zeroNum = 0;        String[][] str = new String[num][2];        if (num >= 2 && num <= 50) {            for(int i=0; i
     
      0; j--) {                        if(!str[i][0].equals(str[j][0]) && !str[i][0].equals("-1") && !str[j][0].equals("-1")) {                            System.out.println(str[i][1] + " " + str[j][1]);                            str[i][0] = "-1";                            str[j][0] = "-1";                            break;                        }                    }                }            } else {                return;            }                    } else {            return;        }    }}